Fluid operated turbine speed control

ABSTRACT

The fluid pressure for operating the turbine speed control governor valve is varied by a fluid vortex control valve, the operation of which is controlled by means responsive to the variable output pressure of a fluid pump operated by the turbine. In the preferred embodiment, the control means includes a second fluid vortex control valve. The action of the second vortex control valve impressed on the first vortex valve greatly increases the sensitivity of the speed control mechanism, increasing the speed of the opening and closing of the governor valve to maintain a more close turbine speed control under varying load conditions.

Unite States Patent Geary July 3, 1973 [5 FLUID OPERATED TURBINE SPEED 3.671.134 6/1972 Boothe 415/13 CONTROL Primary Examiner-C. J. Husar 75 l l mentor Carl H Geary Greensburg Pa Att0rneyHarry G. Martin. Jr. and J. Raymond [73] Assignee: Carrier Corporation, Syracuse, NY. C mi [22] Filed: Oct. 19, 1971 [57] ABSTRACT [21] Appl. No.: 190,512 The fluid pressure for operating the turbine speed control governor valve is varied by a fluid vortex control valve, the operation of which is controlled by means reg% 5" 415/30 4 l gg sponsive to the variable output pressure of a fluid pump 15 17 operated by the turbine. In the preferred embodiment, 1 0 care l the control means includes a second fluid vortex con- 5 6 R f d trol valve. The action of the second vortex control 1 e erences valve impressed on the first vortex valve greatly in- UNITED STATES PATENTS creases the sensitivity of the speed control mechanism, 3,248,043 4/1966 Taplin et a1 415/15 increasing the speed of the opening and closing of the 3,260,271 7/1966 Katz 415/15 governor valve to maintain a more close turbine speed l Boothe t al. control under varying load conditions 3,444,873 5/1969 Prehi et al. 415/15 3,509,773 5/1970 Arnett 415/17 4 Claims, 1 Drawing Figure INVENTOR.

CARL H. EARY BY {%1WMW ATTORNEY FLUID OPERATED TURBINE SPEED CONTROL BACKGROUND OF THE INVENTION In one form of turbine speed control mechanism, the governor valve is operated by fluid pressure which is varied according to the speed of the turbine. The pressurized fluid may be in the form of the output of a pump driven by the turbine, the pressure of the pump output varying with the speed of the turbine and being connected directly to the governor valve actuator. In another arrangement, the pressurized fluid may originate from a source under constant pressure. The fluid is passed to the governor valve through a regulating valve operated by centrifugal mechanism driven by the turbine whereby the pressure of the fluid at the governor valve is varied according to the speed of the turbine. Such speed control mechanisms have a relatively wide range of control and involve a structure costly to manufacture and which require substantial maintenance.

SUMMARY OF THE INVENTION This invention has an object a turbine speed control system wherein the fluid pressure regulating mechanism embodies a particularly simple structure, econom ical to manufacture and substantially free from maintenance. The fluid pressure to the fluid operated control device or governor valve is varied by a fluid vortex control valve which functions to bleed off a portion of the flow of fluid supplied to the speed control device or governor valve from a source of constant pressure. The vortex control valve has a pair of control fluid inlets. The pressure of control fluid to the respective inlets of the vortex control valve is varied in response to the output pressure of a fluid pump operated by the turbine, all whereby the fluid pressure in the line to the governor valve is varied according to the speed of the turbine. The output of the pump is supplied directly to one control fluid inlet of the vortex control valve and also to a control fluid inlet of a second vortex control valve. The other control fluid inlet of the vortex control valve is supplied with fluid under constant pressure.

The other control fluid inlet of the first vortex valve is connected to a fluid supply modified by the second vortex control valve. With this arrangement, the second vortex control valve is effective to apply a differential control fluid supply to the inlet control ports of the first vortex valve to produce a more sensitive, uniform and stable operation of the turbine speed control device.

BRIEF DESCRIPTION OF THE DRAWING The drawing includes a cross sectional view of a conventional fluid operated turbine governor valve and a schematic illustration of a control system embodying my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The conventional valve structure shown in the drawing consists ofa body formed with a flange 11 at one end thereof for attachment to the steam chest of a turbine. A seat structure 12 is mounted in the body 10 and is formed with annular seats 13, 14 engaged by a valve 15 fixed on a stem 16. The stem 16 is slidably mounted in a bushing 17, and at its inner end in the seat structure 12. The stem 16 is reciprocated by a bell crank lever 20, the bight of which is pivotally mounted in a bracket 21 fixed to the valve body and carrying a fluid operated head 23. An actuating stem 25 is slidably mounted in the head 23 and at its lower end is provided with a member 26 adjustable axially along the stem and pivotally connected to the bell crank lever 20.

The upper end of the stem 25 is fixed to a diaphragm 27 which, in conjunction with a cover member 30, forms a fluid tight compartment 31 with which a'conduit 33 has communication. The diaphragm and stem 25 are urged upwardly by a helical compression spring 35. As will be apparent, upward movement of the stem 25 effects movement of the valve 15 to the right toward open position as illustrated in the drawing. The application of pressure from line 33 to the chamber 31 effects downward movement of the stem 25, moving the valve 1.5 into engagement with the seat portions 13, 14 to close off the passage of fluid from the valve inlet 36 to the outlet 37.

The line 33 is connected to a constant pressure source of fluid by line 40 which includes an orifice 41. A branch line 43 extends to the supply inlet 44 of a fluid vortex control valve 45. The valve 45 is formed with a discharge opening 47 and with control inlets 48, 49.

The control inlet 49 is connected by a line 50 to a source 51 of fluid under constant pressure. A branch line 53 extends from line 50 to the supply inlet 55 of a second fluid vortex control valve 57. The valve 57 has a discharge opening 58, connected by a line 60 to a fluid supply reservoir 61. The discharge opening 47 of vortex valve 45 is connected by line 63 to the reservoir 61.

A constant pressure source 64 is connected to the control inlet 65 of valve 57. The control inlet 66 is connected by line 67, to a line 70 extending from the discharge of fluid pump 71 driven by the turbine. The line 70 extends to the control inlet 48 of the vortex valve 45. The control inlet ports 48, 49 are arranged coaxially and at opposite sides of the axis of the supply port 44. Also, the control inlet ports 65, 66 are arranged in like manner relative to the supply inlet port 55.

The turbine driven fluid pump 71 has an intake 73 extending into the reservoir 61. A branch line 75 extends from line 70 to the reservoir, and a flow control valve 77 is connected in the line 75. The valve 77 permits passage of fluid from the pump output line 70 whereby the pressure and volume flow in line 70 is a function of the pump speed and, accordingly, the speed of the turbine. Line 50 from source 51 is also provided with a flow control orifice 80. Also, the line from source 64, is provided with an orifice 81. The pressure and flow volume in line 70 are varied by the adjustment of valve 77 which, in conjunction with the orifices 41, 80 and 81, provides means for setting the design speed of the turbine.

With this initial adjustment, the same pressure is established at control ports 48, 49 in control valve 45. This results in creating a minimum pressure in line 33 with the result that the speed control valve 15 is in open position at the turbine design speed. As the turbine accelerates, the pressure in line 70 and at the control ports 48, 66 increases. Since the jet at port 66 opposes the jet at port 65, there is less resistance to the flow through the valve 57 and, accordingly, there is a pressure drop in line 50 and at control port 49. This results in an increase in the differential control pressure across the vortex valve 45 and an increase in the pressure in line 33 moving the valve further toward close position. The jets at control ports 48, 66 may be referred to as control jets variable according to the speed of the turbine. The jet at control port 49 may be referred to as a bias jet also variable according to the speed of the turbine and the jet at the control port 65 being a fixed bias control jet.

This speed control system is similar to what might be described as a push/pull effect, reducing the reaction time between change of turbine speed and operation of the governor valve. Also, the vortex control valve 57 serves to effect a vernier adjustment of the vortex valve 45. These features of the control system result in a more rapid, uniform and stable operation of the governor valve.

While a preferred embodiment of this invention has been described for purposes of illustration, it will be appreciated that this invention may be otherwise embodied within the scop of the following claims.

I claim:

1. A fluid pressure operated speed control system for a turbine or the like including valve means for controlling the flow of operating fluid to the turbine to control turbine speed, fluid pressure responsive means for operating said valve means, a fluid vortex control valve having a fluid supply inlet port, a fluid discharge opening and first and second control fluid inlets, arranged co-axially and positioned at opposite sides of the axis of said supply inlet port, a fluid supply line connected to said fluid pressure responsive means and having a bleed-off branch connected to the supply inlet port of said vortex control valve, said fluid pressure responsive means being operable to operate said valve means in response to the fluid pressure in said fluid supply line, said vortex control valve being operable to vary the flow of fluid from said bleed-off branch and the pressure in said fluid supply line according to differential pressures applied to said control inlet ports of said vortex valve, a fluid pump operated by said turbine and having an output pressure variable according to the turbine speed and control means operable to supply differential pressures to said control inlets according to said pump output pressure.

2. A speed control system as set forth in claim 1 wherein the output pressure from said pump is applied directly to one of said control inlets and means operable in response to increase in pump output pressure to proportionately decrease the fluid pressure applied at said other control inlet.

3. A speed control system as set forth in claim 1, wherein said control means includes a second fluid vortex control valve having a supply inlet port, a discharge opening and first and second fluid inlet ports, the output of said pump being connected to a control inlet port of each of said vortex control valves, a control line extending from a source of constant pressure to the other inlet port of said first vortex control valve and having a bleed-off branch connected to the supply port of said second vortex control valve, and a line from a source of fluid at constant pressure connected to the other control port of said second vortex control valve.

4. A fluid pressure operated speed control system for a turbine or the like, including valve means for controlling the flow of operating fluid to the turbine to turbine speed, fluid pressure responsive means for operating said valve means, a fluid vortex control valve having a fluid supply inlet port, a fluid discharge opening and fluid control means for controlling the flow of fluid through said fluid vortex control valve, a fluid supply line connected to said speed control device and having a bleed-off branch connected to the supply inlet port of said vortex control valve, said fluid pressure responsive means being operable to operate said valve means in response to the fluid pressure in said fluid supply line, a fluid pump operated by said turbine and having an output pressure variable according to the turbine speed, the output from said pump being connected to said fluid control means of said vortex control valve, said vortex control valve being operable in response to the pressure of the output of said pump to vary the flow of fluid from said bleed-off branch to said fluid discharge opening according to said pump output pressure.

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1. A fluid pressure operated speed control system for a turbine or the like including valve means for controlling the flow of operating fluid to the turbine to control turbine speed, fluid pressure responsive means for operating said valve means, a fluid vortex control valve having a fluid supply inlet port, a fluid discharge opening and first and second control fluid inlets, arranged co-axially and positioned at opposite sides of the axis of said supply inlet port, a fluid supply line connected to said fluid pressure responsive means and having a bleed-off branch connected to the supply inlet port of said vortex control valve, said fluid pressure responsive means being operable to operate said valve means in response to the fluid pressure in said fluid supply line, said vortex control valve being operable to vary the flow of fluid from said bleed-off branch and the pressure in said fluid supply line according to differential pressures applied to said control inlet ports of said vortex valve, a fluid pump operated by said turbine and having an output pressure variable according to the turbine speed and control means operable to supply differential pressures to said control inlets according to said pump output pressure.
 2. A speed control system as set forth in claim 1 wherein the output pressure from said pump is applied directly to one of said control inlets and means operable in response to increase in pump output pressure to proportionately decrease the fluid pressure applied at said other control inlet.
 3. A speed control system as set forth in claim 1, wherein said control means includes a second fluid vortex control valve having a supply inlet port, a discharge opening and first and second fluid inlet ports, the output of said pump being connected to a control inlet port of each of said vortex control valves, a control line extending from a source of constant pressure to the other inlet port of said first vortex control valve and having a bleed-off branch connected to the supply port of said second vortex control valve, and a line from a source of fluid at constant pressure connected to the other control port of said second vortex control valve.
 4. A fluid pressure operated speed control system for a turbine or the like, including valve means for controlling the flow of operating fluid to the turbine to turbine speed, fluid pressure responsive means for operating said valve means, a fluid vortex control valve having a fluid supply inlet port, a fluid discharge opening and fluid control means for controlling the flow of fluid through said fluid vortex control valve, a fluid supply line connected to said speed control device and having a bleed-off branch connected to the supply inlet port of said vortex control valve, said fluid pressure responsive means being operable to operate said valve means in response to the fluid pressure in said fluid supply line, a fluid pump operated by said turbine and having an output pressure variable according to the turbine speed, the output from said pump being connected to said fluid control means of said vortex control valve, said vortex control valve being operable in responSe to the pressure of the output of said pump to vary the flow of fluid from said bleed-off branch to said fluid discharge opening according to said pump output pressure. 